This invention relates to a blowing apparatus for delivering gaseous and solid materials to a hot melt during a refining process. More particularly, this invention relates to a new and improved blowing lance for safely and simultaneously delivering oxygen and carbonaceous materials to a metal bath both above and below the surface of the melt.
During a typical refining process, oxygen is delivered to the hot melt and is utilized for a variety of functions. The particular function determines the manner of delivery. For example, a quantity of oxygen needed for refining the metal will be delivered below the surface of the pool (by a pressurized stream which penetrates into the bath) to ensure the interaction of the oxygen with the carbon. This reaction will ultimately form carbon monoxide gas. As a result of the carbon monoxide formed therefrom, an additional quantity of oxygen is distributed above the surface of the metal pool for the purpose of burning or combusting the newly formed carbon monoxide. Solid or particulate carbonaceous material entrained in a carrier gas is also delivered to the metal pool in order to recarburize the hot melt. The carbon monoxide combustion and oxidation of the carbonaceous material creates a release of energy which is ultimately and efficiently used to melt large quantities of scrap added to the pool.
It is well known to those skilled in the art that the simultaneous delivery of almost pure oxygen and a carbonaceous material through the same delivery device in an environment where the temperatures exceed 1400.degree. C. is extremely difficult and harzardous and requires precautionary measures. For example, extreme care must be taken in order to avoid leaks between different delivery tubes which might lead to explosive contact between the oxygen and carbon materials. In that connection, it must be borne in mind that the entrained carbonaceous particulate material is highly abrasive, and could wear through a spacer or divider wall.
Other difficulties and precautions become apparent when a cooling system is utilized. While it is advantageous to incorporate a cooling system into the delivery device, the cooling circuit must be minimized with respect to space and quantity of cooling fluid to be used. The minimization of these two factors is crucial because, in the event of a leak or break in the cooling system, the amounts of fluid reaching the metal pool must be limited so as to avoid contamination of the melt and damage to the refining process.
Finally, although the tasks to be performed by the delivery device are extremely complex, the device should preferably have a relatively simple construction which should be inexpensive to manufacture.